This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Hemolysin is a toxin of E. Coli that induces lysis of red blood cells from different animal species. Here we test the influence of bilayer composition on protein interaction with red blood cells of sheep, horse and rabbit, and the effect of cholesterol depletion on cells shape and behavior. We analize these parameters by Laurdan General Polarization measurements at the microscope